Topping up Hydraulic Steering Fluid

[Mike k]

Hi all

as part of the service pack, my supplier sent me some ''power trim fluid''
I am guessing this is for the steering but through my manuals there is no instruction how to top it up.There is a plastic screw top on the helm behind the wheel which when taken off you can see mechanisms. There is some rams in the stern of the boat which operate the rudder when steering which have some little plastic red end caps on .Not sure whether this is power steering or hydraulic and whats the difference anyway?


Any advice on 1) Does this fliud sound right for the job
2) do i top up through the plastic screw top
3) Any topping up techniques
4) how do you know if it needs topping up and is it a problem to top up when not needed

Any help most gratefully recieved.

 

[sarabande]

it sounds as if you have an end to end hydraulic system.

I had a thirty year old steering system that never leaked, but I decided to drain and replace the fluid. Fluids spec had changed since the original design, and in the end I used an agricultural general purpose hydraulic fluid of the same SAE rating.

The topping up nut was very inaccessible, so I used a 250ml drenching syringe and some thin flexible rubber tubing to reach the filler.

Like this but larger
http://www.net-tex.co.uk/product_page.cfm?pid=96&men=1

available at all agr merchants


Draining was done by loosening a bleed screw on the rudder quadrant to enable the old fluid to flow through, slowly and to drip into a bucket below.

I was careful not to allow the level to fall below the pump behind the wheel and entrain air.

Top up at the highest point in the system - after you have made sure that there is no leakage elsewhere, as hydraulic fluid is very sticky.

The symptoms of low fluid level are the wheel spinning rather freely, - and of course reduced action at the rudder end.

 

[spannerman]

Having replaced literally dozens of Volvo's famous steering cylinders and hoses (4 this week!) I have found an easy way to top up the fluid, I have a standard plastic pepsi bottle and a plastic threaded fitting which screws into the helm pump and about 18" of clear flexible tubing the other end has a fitting on the threads of the bottle. With the bottle half full I invert it and twirl the steering lock to lock and it pulls in the fluid it needs, and the air comes out, if its a Volvo D4 or D6 it has power steering then the engine needs to be running to get the system bled out properly.
You will know when its right as the wheel will have a smooth even load lock to lock, if it is lumpy and makes a clicking sound then you don't have enough fluid in the resevoir and there is still air present.
If you can see the mechanism under the filler plug then its too low and may just need topping up until it just covers the mechanism as you need a little room for expansion.
If the steering clicks then its got low enough to draw in air, if its a flybridge then this operation must be done at the upper helm.

 

[Mike k]

thanks for the posts - sorry iof i havent fully grasped the advice but just to confirm --that plug in the helm is this in fact the filler plug? I dont have a flybridge so its the highest point.
The bottle that the fluid came in has a pointy neck which would fit into the unscewed plug hole - can i just top up like that so it covers the visible mechanism then rotate the helm each way and replace the plug??

 

[fisherman]

I had a bit of a leak, needing constant attention, so replaced the filler plug with a BSP fitting and pipe tail, then flexi tube up to a bottle. This is normal on some outfits. In my case the bottle is a car cooling expansion tank.